"I'm holding up fine," the actor PEOPLE at the New York City premiere of his new film, Beyond a Reasonable Doubt. "It's a very difficult situation and painful, as I'm sure any mother or father of a substance abuser knows. So we're doing the best we can."

Cameron, 30, was arrested July 28 and charged with dealing methamphetamine, also known as crystal meth. He was released on bail and confined to a New York apartment, but a judge later sent him to the Metropolitan Correctional Center after authorities discovered that his girlfriend, Kelly Sott, attempted to smuggle him heroin hidden inside an electric toothbrush.

Asked how Cameron is holding up now, Douglas told PEOPLE, "given the circumstances, as well as can be expected."

Beyond a Reasonable Doubt's director, Peter Hyans, heaped praise on his star's handling of a difficult situation. "He handles everything with honesty and with grace. He has the kind of grace that I honestly don't think you can learn," he said. "He has the kind of grace that is somehow or other in his DNA."